May the Force Be with You

This odd-looking device is a medical marvel. It is used to detect radiation in the human body. The radiation is given off by radioactive isotopes, or radioisotopes, that have been injected into a patient.

Why It Matters

Standard X rays are very useful for some purposes, such as diagnosing broken bones. But X rays just show structures of the body. Even CT and MRI scans mainly just show the body’s structures.

Medical scans that detect radioactive isotopes, called PET scans, not only show structures of the body. They also show how the structures are working. They can detect cancer cells, for example, because they use more energy than normal cells.

Credit: dion gillard

Source: http://www.flickr.com/photos/diongillard/2551737455/

License: CC BY-NC 3.0

The images produced by a PET scan highlighting various organs in the body
[Figure2]

PET scans would not be possible without the weak nuclear force. This is the force inside the atomic nucleus that can change a proton into a neutron, or vice-versa. In doing so, the weak force changes one type of atom into another and releases radiation. This is called radioactive decay.

Watch this entertaining video to learn how the weak force is involved in radioactive decay: